Quantum dots (QDs) can also be called nanocrystals, and are nanoparticles consisting of group II-VI or group III-V elements. The particle sizes of quantum dots are generally between 1˜20 nm. In quantum dots, because electrons and holes are confined in quantum, the structure of continuous energy bands is turned into the structure of discrete energy bands, and thus quantum dots can emit fluorescence after being excited.
The emission spectra of quantum dots can be controlled by altering the size of the quantum dots. By altering the size and chemical composition of quantum dots, their emission spectra can be expanded to cover the whole visible region. By taking CdTe quantum dots as an example, when the particle size grows from 2.5 nm to 4.0 nm, the emission wavelength can make a red shift from 510 nm to 660 nm.
Currently, with the light emitting property of quantum dots, quantum dots can be used as molecular probes in fluorescent labeling and can also be used in a display device. Monochromatic quantum dots are used as the light source of the backlight module of a liquid crystal display panel, in which after excited by a blue LED, the monochromatic quantum dots emit monochromatic light which mixes with the blue light to form a white background light, which has large light gamut and can improve the display quality.
Because nano-scale quantum dots possess poor dispersion capability in organic solvents, upon subsequent pattern forming, the quantum dots will aggregate, resulting in quenching, which severely reduce the quantum yield. Therefore, currently there has been no design in which quantum dots are used inside a liquid crystal display panel.